Ganesha

Ganesha, the Elephant-God, is the son of Lord Shiva and Goddess Parvati. He is the first to be worshipped before any major endeavors such as starting a new profession, laying foundation of a building etc.

Attributes
Lord Ganesha has an elephant's head with one tusk (or a broken second one). His vehicle is a mouse. He is generally portrayed with four hands - one holding a trident, one with a shell, one with a flower and one with laddu (an Indian sweet).

Story behind Ganesha having an elephant's head
There are several legends that surround Ganesha's head but the most popular one goes as follows.
Once when Goddess Parvati was going to take her bath, she created Ganesha and asked him to guard. When Shiva, coming back from a journey sought entry into the house, Ganesha being unaware of his identity refused entry, leading to Shiva cutting his head off. When Parvati explained that Ganesha was actually their son, Shiva asked to be brought back the head of a child whose mother was sleeping with her back towards it. An elephant cub whose mother wa sleeping in this posture was found and his head was fixed onto Ganesha's shoulders.

It is believed that it was Lord Ganesha who instituted the four castes and the four Vedas. There are also several legends behind Ganesha's preference among other Gods in the order of worship. One story says that when Paravati saw an elephant's head being affixed to Ganesha she was inconsolable, leading to Brahma in order to pacify her, announcing that Ganesha will get precedence over other Gods in worship. Ganesha is also believed to be the God of learning and wisdom. He has two wives: Riddhi (Prosperity) and Siddhi (Success).

As Ganesha is associated with auspiciousness, success, prosperity and overcoming difficulties, the lord's image can be seen on letter heads, account books, calendars, gates of houses and places of business and so on.

Ganesha's birthday on fourth day of Bhadrapad (the sixth month of the Hindu Lunar calendar) is celebrated throughout India as Ganeshchaturthi. The celebrations are at a much greater scale in Maharashtra and India's south. The culmination of these festivities is immersion of Ganesha's clay idols into a river or sea.